66849961 has 8 divisors (see below), whose sum is σ = 71523200. Its totient is φ = 62292240.

The previous prime is 66849949. The next prime is 66850073. The reversal of 66849961 is 16994866.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66849961 - 2⁵ = 66849929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66849931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27681 + ... + 29998.

It is an arithmetic number, because the mean of its divisors is an integer number (8940400).

Almost surely, 2^66849961 is an apocalyptic number.

66849961 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

66849961 is the 3657-th centered decagonal number.

It is an amenable number.

66849961 is a deficient number, since it is larger than the sum of its proper divisors (4673239).

66849961 is a wasteful number, since it uses less digits than its factorization.

66849961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57759.

The product of its digits is 559872, while the sum is 49.

The square root of 66849961 is about 8176.1825444397. The cubic root of 66849961 is about 405.8514040398.

The spelling of 66849961 in words is "sixty-six million, eight hundred forty-nine thousand, nine hundred sixty-one".